Such an arrangement is known from DE 10 2014 201 076 B3 (reference [1]).
NMR spectroscopy is an efficient method for instrumental analysis. In this method, RF (radio frequency) pulses are irradiated into a measurement sample, which is placed in a strong static magnetic field, causing the alignment of nuclear spins in the measurement substance. The RF reaction of the measurement sample is then measured. From this, information is obtained integrally over a certain area of the measurement sample, the so-called active volume, and this information is evaluated in order to determine the chemical composition.
In NMR spectroscopy of samples of solid bodies, significant line broadening in the measured NMR spectra is observed, which is due to anisotropic interactions between nuclei in the sample. In the case of solid samples, it is known to rotate, at a high frequency (typically a few kHz), the measurement substance during the NMR measurement at the so-called “magic angle” of 54.74° with respect to the direction of the static magnetic field (MAS, “magic angle spinning”). In this way, line broadening due to dipolar interactions and chemical displacement may be reduced.
The measurement sample is normally composed of a cylindrical sample tube, called a rotor, which contains the measurement substance to be analyzed in a solid or liquid form. In order to perform the measurement, the rotor with the measurement substance is transferred into a stator, and is set in rotation relative to the stator, the rotor hanging within the stator. To this end, suitable gas flows are usually used. In order to radiate RF-pulses into the measurement substance and/or to receive RF signals from the measurement substance, a RF-coil arrangement is provided, which surrounds the stator.
Conversely, DE 2014 201 076 B3 (already cited at the outset) proposes a shuttle, the outer contour of which has a geometric shape such that, on the one hand, the shuttle can be used with a transport system which is designed for the transport of an HR-NMR sample spinner comprising an inserted sample tube and, on the other hand, the shuttle is also designed for the transport of an NMR MAS rotor, the shuttle including a locking apparatus for the NMR MAS rotor. This locking apparatus is formed in such a way that, when placing the shuttle on the NMR MAS probe head, the NMR MAS rotor is released by unlocking the locking apparatus and can be transferred to and received by the NMR MAS probe head.
This improved transport device according to reference [1] thus solves, for instance with respect to the system according to reference [2], the technical problem, which consists in allowing rapid switching from NMR spectroscopy of liquids to NMR spectroscopy of solids and vice versa, without requiring alterations of the transport system, but only by replacing the probe head. In both cases it is now possible to use the same transport system and in particular also the same automation equipment for the sequential feeding of a high number of samples, without alterations, both with existing NMR MAS probe heads and with NMR MAS rotors.
A special embodiment of the transport device according to the aforementioned DE 10 2014 201 076 B3 is additionally characterized in that an additional apparatus is present, which makes it possible to detect from the outside if the shuttle is currently loaded with an NMR MAS rotor. For this purpose, according to this prior art, an additional component is displaced by the NMR MAS rotor inserted in the shuttle in such a manner that it can be detected from the outside of the shuttle, visually or by means of sensors, whether or not the shuttle is loaded with an NMR MAS rotor.